The second round of Democratic candidates will debate on Thursday in Miami. Here are some quick facts about them.

There will be over 153 years of political experience on the debate stage.

The candidates include:

• 1 Vice President: Biden
• 4 Senators: Harris, Sanders, Bennet, Gillibrand
• 1 Congressman: Swalwell
• 1 Mayor: Buttigieg
• 1 entrepreneur: Yang
• 1 author & activist: Williamson

The candidates range in age from 37 to 77 years old.

• Oldest candidate: Sen. Bernie Sanders, 77 years old
• Second oldest candidate: Former Vice President Joe Biden, 76 years old
• Youngest candidate: Mayor Pete Buttigieg, 37 years old
• Second youngest candidate: Rep. Eric Swalwell, 38 years old

They also differ in terms of experience.

• Most political experience: Former VP Joe Biden, 46 years
• Neither best-selling author and activist Marianne Williamson nor entrepreneur Andrew Yang have ever held elected office.
• Mayor Pete Buttigieg will be the lone candidate on the stage tonight who has served in the United States military.

Some candidates share a common background.

• 7 candidates attended law school: Biden, Bennet, Buttigieg, Harris, Gillibrand, Swalwell and Yang.
• Sen. Sanders, Biden, Gillibrand and Bennet have all served over 10 years in the United States Senate.
• Sen. Sanders and Sen. Harris serve together on the U.S. Senate Budget Committee.
• Sen. Harris and Sen. Bennet serve together on the U.S. Senate Intelligence Committee.
• Sen. Gillibrand and Sen. Bennet serve together on the U.S. Senate Agriculture Committee.

One notable friendship:

• Hickenlooper and Bennet have been friends for more than 15 years. They worked together when Hickenlooper served as Denver mayor, and Bennet eventually became the city's superintendent of public schools.

Saul Loeb/AFP/Getty Images

The candidates debating on Thursday are:

Former VP Joe Biden

Political Experience:

• Vice President of the United States: 8 years
• United States Senator, Delaware: 36 years
• New Castle County Council: 2 years

Personal quick facts:

• 76 years old
• Born in Scranton, Pennsylvania
• University of Delaware graduate
• Syracuse University law school
• Gold Medal of Freedom (2009)
• Presidential Medal of Freedom (2017)
• Spouse: Jill Biden, an English teacher
• 4 children
• Biden's first wife, Neilia, and their daughter, Naomi, died in a car accident in 1972, and his son, Beau, died in 2015

Sen. Michael Bennet

Political Experience:

• United States Senate, Colorado: 10 years
• Former chair of the Democratic Senatorial Campaign Committee
• Served as Superintendent of Denver Public Schools

Personal quick facts:

• 54 years old
• Born in New Delhi, India
• His father was an an aide to the U.S. Ambassador to India; his mother is a Holocaust survivor who emigrated to the United States from Poland in 1950
• Wesleyan University graduate
• Yale University law school graduate
• Spouse: Susan Daggett
• Children: 3

via Reuters

Mayor Pete Buttigieg

Political Experience:

• Mayor of South Bend, Indiana: 7 years
• Conference director for former U.S. Secretary of Defense William Cohen at the Cohen Group:
• Consultant at McKinsey & Company
• Volunteered on President Obama’s 2008 presidential campaign

Military Experience:

• Navy Reserve: 2008-2017
• Deployed to Afghanistan for 7 months in 2014

Personal quick facts:

• 37 years old
• Born in South Bend, Indiana
• Fluent in five languages
• Harvard University graduate
• Pembroke College, Oxford graduate
• Spouse: Chasten Buttigieg
• If elected, Buttigieg would be the first openly-gay president

Sen. Kirsten Gillibrand

Political Experience:

• United States Senator, New York: 10 years
• Holds the seat once occupied by Hillary Clinton
• U.S. House of Representatives, New York: 2 years
• Special Counsel to Secretary of Housing and Urban Development (HUD)

Personal quick facts:

• 52 years old
• Born in Albany, New York
• Dartmouth College graduate
• University of California, Los Angeles law school graduate
• Partner at Boies, Schillfer & Flexner
• Spouse: Jonathan Gillibrand
• Children: 2
• If elected, Gillibrand would be the first female president

Mike Segar/Reuters

Sen. Kamala Harris

Political Experience:

• United States Senator – California: 3 years
• Attorney General of California: 6 years
• District Attorney of San Francisco: 7 years

Personal quick facts:

• 54 years old
• Born in Oakland, California
• Howard University graduate
• University of California, Hastings law school graduate
• Spouse: Douglas Emhoff
• Stepchildren: 2
• Harris’ parents immigrated from Jamaica and India
• Sister: Maya Harris served as a policy advisor for Hillary Clinton’s 2016 presidential campaign
• If elected, Harris would be the first female president

Former Gov. John Hickenlooper

Political Experience:

• Governor of Colorado: 8 years
• Chair of the National Governors Association: 1 year
• Mayor of Denver: 8 years

Personal quick facts:

• 67 years old
• Wesleyan University graduate
• Born in Narberth, Pennsylvania
• Spouse: Robin Pringle Hickenlooper,
• Children: 1
• Avid squash player
• Suffers from prosopagnosia or also referred to as “face blindness.”

Sen. Bernie Sanders

Political Experience:

• United States Senator, Vermont: 12 years
• U.S. House of Representatives, Vermont: 16 years
• Mayor of Burlington: 8 years

Personal quick facts:

• 77 years old
• Born in Brooklyn, New York
• 2016 Presidential Candidate
• Brooklyn College graduate
• University of Chicago graduate
• Spouse: Jane O’Meara Sanders
• Children: 4

Rep. Eric Swalwell

Political Experience:

• U.S. House of Representatives, California: 6 years
• Dublin City Council: 3 years

Personal quick facts:

• 38 years old
• Born in Sac City, Iowa
• Attended Campbell University in North Carolina on a soccer scholarship. He broke both thumbs and his scholarship ended.
• University of Maryland, College Park graduate
• University of Maryland, Baltimore law school graduate
• Spouse: Brittany Watts
• Children: 2

Marianne Williamson

Political Experience:

• Ran unsuccessfully for U.S. House seat in California’s 33rd district in 2014

Career: Author and activist

• Author of 13 books
• Founder of Project Angel Food: volunteer food delivery that serves people with HIV/AIDS
• Frequent guest on The Oprah Winfrey Show
• Co-founded the Peace Alliance: a national grassroots education and advocacy group

Personal quick facts:

• 66 years old
• Born in Houston, Texas
• Pomona College graduate
• Children: 1
• If elected, Williamson would be the first female president

Andrew Yang

Political Experience:

• Received two awards from President Barack Obama. In 2015, Yang received the President Ambassador for Global Entrepreneurship, a collaborative initiative tasked to measure entrepreneurial growth. In 2012, Yang received the Champions of Change award. Champions of Change highlighted communities to rise to the challenges of the 21 century.

Career: Attorney and entrepreneur

• Founder of Venture for America

Personal quick facts:

• 44 years old
• Born in Schenectady, New York
• Brown University graduate
• Columbia University law school graduate
• Son of two immigrant parents from Taiwan
• Spouse: Evelyn Yang
• Children: 2