(CNBC) Only 10 Democrats will take the stage in next months 2020 presidential primary debate as the jammed field starts to shrink. ABC News on Thursday unveiled the lineup for the debate set for Sept. 12 in Houston. Unlike the past two debates that featured 20 Democrats over two nights the next event will see all qualified candidates on one stage. In a primary where national polling has found three contenders separated from the rest of the pack the debate gives lesser-known candidates a chance to make their case with a national platform. It will also for the first time put frontrunner Joe Biden on the same stage as all of the other top-tier candidates who aim to cut into the former vice presidents edge. Here are the candidates who qualified for the Houston debate ordered by their standing in the RealClearPolitics national polling average: Biden Sen. Bernie Sanders I-Vt. Sen. Elizabeth Warren D-Mass. Sen. Kamala Harris D-Calif. South Bend Ind. Mayor Pete Buttigieg Entrepreneur Andrew Yang Sen. Cory Booker D-N.J. Former Rep. Beto ORourke Former Housing and Urban Development Secretary Julian Castro Sen. Amy Klobuchar D-Minn.