The 10 leading Democratic presidential candidates on Thursday will take the stage together for the first time as they face off in the party's third 2020 presidential primary debate.

Unlike the prior debates, this one, which is sponsored by ABC and takes place in Houston, will feature all the highest-polling candidates, including former Vice President Joe Biden, Massachusetts Sen. Elizabeth Warren, California Sen. Kamala Harris and Vermont Sen. Bernie Sanders.

In the first two debates, the field of 20 was split over two nights into 10 each night, and included California Rep. Eric Swalwell, Former Colorado Gov. John Hickenlooper, New York Sen. Kirsten Gillibrand and Washington Gov. Jay Inslee, who have since dropped out.

Here's everything you need to know about the third debate.

When, where is the Democratic debate?

The debate is being held at Texas Southern University on Thursday night at 8 p.m. ET and will be co-hosted by ABC and Univision. Viewers should stock up on provisions — it's slated to run for three hours.

ABC's George Stephanopoulos, "World News Tonight" anchor David Muir, network correspondent Linsey Davis and Univision's Jorge Ramos will be the moderators.

Who qualified?

The 10 candidates who qualified by having both 130,000 individual donors and reaching at least 2 percent in four qualifying polls are Biden, Sanders, Warren, Harris, New Jersey Sen. Cory Booker, Minnesota Sen. Amy Klobuchar, Mayor Pete Buttigieg of South Bend, Indiana, former Housing Secretary Julián Castro, former Texas Rep. Beto O'Rourke and entrepreneur Andrew Yang.

Who's next to whom?

Where the candidates stand on stage was determined by polling averages based on the last 10 polls certified for qualification by the Democratic National Committee. The candidates with the highest polling averages — Biden and Warren — will be center stage. The overall order from left to right is Klobuchar, Booker, Buttigieg, Sanders, Biden, Warren, Harris, Yang, O'Rourke and Castro.

Who's out?

Candidates who failed to qualify for the Houston debate but had made it into the second debate — when participants needed to get 65,000 individual donors or hit 1 percent inthree qualifying polls — include Reps. Tulsi Gabbard of Hawaii and Tim Ryan of Ohio, Colorado Sen. Michael Bennet, Montana Gov. Steve Bullock, New York City Mayor Bill de Blasio, author Marianne Williamson and former Maryland Rep. John Delaney.

What's the format?

Candidates will make opening statements, but there will be no closing remarks, the network says.

They will have a little more time to answer questions than in the earlier debates — one minute and 15 seconds for direct responses to questions and 45 seconds for rebuttals. That's up from the one-minute responses and 30-second rebuttal times in the first two debates, which were hosted by NBC and CNN, respectively.

How can I watch?

The three-hour debate will air live on ABC and Univision and their streaming platforms. NBCNews.com will live-blog throughout the night, offering live updates, fact checks and analysis.

When is round 4?

The fourth debate is scheduled for Oct. 15, with a second night on Oct. 16 if needed. Candidates have to reach the same criteria as Thursday's debate to qualify, but the field is already looking bigger. Billionaire Tom Steyer, who is not participating in Thursday's debate, says he's reached the polling to qualify. Gabbard appears to have enough donors, but still needs to reach 2 percent in two more qualifying polls to make the cut. Williamson also appears to have hit the donor threshold, but needs three more polls to make the stage. The deadline to qualify is Oct. 1.