Democratic debate: Only 6 candidates qualify for 1st face off of 2020

Only six presidential candidates were invited to take the stage at the seventh Democratic Primary Debate this Tuesday, according to the Democratic National Committee.

Those candidates are, in alphabetical order, Vice President Joe Biden, Mayor Pete Buttigieg, Sen. Amy Klobuchar, Sen. Bernie Sanders, billionaire Tom Steyer and Sen. Elizabeth Warren.

Unlike the last debate, businessman Andrew Yang will not be invited to participate.

RELATED: Democratic debates scheduled for 2020

The candidates were selected by qualification criteria agreed to by the hosts, according to the DNC, but the exact criteria were not specified.

Next week's debate, hosted by CNN and The Des Moines Register, will take place Jan. 14 at Drake University in Des Moines, Iowa, and will be moderated by CNN's Wolf Blitzer and Abby Phillip as well as The Des Moines Register's Brianne Pfannenstiel.

Sanders has the lead over his fellow Democrats into this critical stretch less than a month away from the Iowa Caucus, according to the latest CNN/The Des Moines Register/Mediacom poll.

Twenty percent of likely Democratic caucus-goers would vote for the Vermont Senator, according to the poll, followed by Warren at 17%, Buttigieg sliding down to 16% and Biden coming in at 15%.

This is still a tight race -- nearly half of Iowa voters said they have not made a firm decision on who they plan to support.