(NewsNation) — Voters in Houston will choose their mayor Monday from a crowded field of 18 candidates, all looking to replace the current mayor, Sylvester Turner, who cannot run again due to term limits. The big city race has candidates pitted against each other on policies around crime, infrastructure, budget shortfalls and affordable housing.

The top candidates are two long-time Democrats: U.S. Rep. Sheila Jackson Lee and state Sen. John Whitmire, who have been fixtures in Texas politics.

A recent poll shows Whitmire leading Jackson Lee by a few percentage points, but many voters remain undecided. In a recent survey by the University of Houston, Whitmire led Jackson Lee 34% to 31%, within the margin of error. All other candidates combined got 12%.

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Houston, with a population of 2.3 million, is the most populous city in Texas and the most diverse city in the United States. At that size, the mayor of Houston — a nonpartisan office — is in charge of a larger population than at least a dozen American states.

Polls close at 6 p.m. ET Tuesday. The graphic below will be updated as results come in.

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