Assistant Returning Officer K Habung said Mithi bagged 47 votes, Siga secured 10 and two votes were found invalid.
Altogether 59 votes were polled out of the total 60.
Mithi won the seat for the second consecutive term.
The Congress won 42 seats in the April 9 Assembly elections in the state, while BJP got 11 and PPA five. There are also two independent MLAs in the 60-member House. However, one Congress MLA has passed away.