Even though 12 candidates already have qualified, the Democratic presidential debate this month in Westerville will be limited to a single night.

"I think it's the right decision," said Ohio Democratic Chairman David Pepper.

"We're at a point where voters want to see all the candidates, particularly the leading candidates, on the stage at the same time."

But it also means that time for each candidate will be at a premium.

Underscoring the importance of the week, Democratic National Committee Chairman Tom Perez has confirmed he will speak at the party's state dinner Oct. 13, the Sunday before the debate. Some of the candidates are expected as well. Individual tickets to the event at the Greater Columbus Convention center are $250; $500 includes dinner plus admission to a "sponsors reception."

The party's fourth debate is set for 8 p.m. Oct. 15 in Otterbein University's Rike Center, with CNN anchors Erin Burnett and Anderson Cooper and New York Times national editor Marc Lacey serving as moderators.

"To address several inquiries we have received we are writing to let you know that, pending a final decision after the certification deadline, it is the intention of the DNC and our media partners to hold the October debate over one night," the Democratic National Committee wrote Sept. 27 in an email to the candidates.

The network did not say how long the debate would last, but the previous one-night event stretched three hours.

Candidates were given until Oct. 1 to meet the qualifying thresholds for poll results and campaign contributions.

Twenty candidates made the stage for the first two Democratic debates, split into 10 apiece over two nights. The third debate held in September in Houston had 10 candidates, all on one night.

A Democratic National Committee official told CNN several factors were taken into account in deciding to focus on one night.

"Our goal has always been to expand viewership, and we also believe that one night worked well for this last debate," said the official, speaking on background.

Those who had qualified as of Sept. 27 included former Vice President Joe Biden, New Jersey Sen. Cory Booker, South Bend Mayor Pete Buttigieg, former Housing and Urban Development Secretary Julian Castro, Hawaii Rep. Tulsi Gabbard, California Sen. Kamala Harris, Minnesota Sen. Amy Klobuchar, former Texas Rep. Beto O'Rourke, Vermont Sen. Bernie Sanders, businessman Tom Steyer, Massachusetts Sen. Elizabeth Warren and businessman Andrew Yang.