30% of Democratic voters do not know who they want to be the 2020 Democratic presidential nominee, according to Insider polling.

This means there are a lot of undecided voters who could potentially be won over as the race boils down to a battle between Sen. Bernie Sanders and former Vice President Joe Biden.

The poll also found that 27% of Democratic voters said they'd be satisfied with only Sanders, while 23% said just Biden, and 19% said they'd be satisfied with either the Vermont senator or the former vice president.

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Roughly one-third of Democratic voters do not know who they want to be the 2020 Democratic presidential nominee, according to an aggregation of seven Insider polls taken between January and March.

For the past several months, Insider has been conducting a recurring SurveyMonkey Audience poll to track the state of the 2020 Democratic primary field. You can download every poll here, down to the individual respondent data. (Read more about how the Insider Democratic primary tracker works here).

We ask respondents to select as many contenders as they want when asked who they'd be satisfied with in the event they became the Democratic nominee. We focus on respondents who said they are registered to vote and intend to participate in their state's primary or caucus.

The poll showed there are more Democratic voters who are unsure of who they want than those who said they would be satisfied with either Sen. Bernie Sanders or former Vice President Joe Biden.

All told, half of the Democratic voters liked Sanders and a little less than half liked Biden. But there's lots of overlap.

About 19% said they'd be satisfied with both the Vermont senator and the former vice president atop the ticket. (Good for them! They should be pretty happy right now.)

Meanwhile, 27% said that between Bernie and Biden, they'd be satisfied with Sanders alone.

23% said Biden if only Sanders and Joe were in the race.

But most interestingly, following the various exits of contenders, 30% of Democrats don't have a candidate anymore.

That 30% didn't indicate satisfaction with Biden or Bernie. This doesn't necessarily mean they're dissatisfied with Sanders or Biden, just that their awareness has not yet risen to satisfaction.

The race has rapidly morphed from a battle between a huge, diverse crop of candidates to a head-to-head matchup between Sanders and Biden. This poll shows there are a lot of undecided voters out there for them to win over, but also underscores how messy things could get moving forward.

With Biden emerging from Super Tuesday with a fairly solid, but not insurmountable, lead in delegates (530 for Biden vs 456 for Sanders), the self-declared democratic socialist arguably has the most to gain by targeting the 30% of voters who are unsure of who they want to back.