Voting for the reserved constituency (SC) was postponed after SP candidate Chandrashekhar Kanaujia died of heart attack while campaigning in Ambedkarnagar on February 12.
Polling in the constituency was originally scheduled for February 27 in the fifth of the seven-phase state Assembly elections.
According to the law, if a candidate of a recognised party dies, it is given time to field a new candidate and the polling fixed for another date.
The seat is currently held by Bhim Prasad Sonkar of the SP, but he was not fielded by the party this time.
Besides, there are nine candidates, including those from BJP and BSP, in the fray.
In view of this polling, the Election Commission postponed telecast of exit polls till 5:30 pm today.