Section 10(5)(a) in The Orissa Grama Panchayats Act, 1964
(a)the offices of Sarpanchas in Grama Panchayats shall be reserved for the Scheduled Castes and the Scheduled Tribes and the number of offices so reserved for the Scheduled Castes and the Scheduled Tribes shall bear, as nearly as may be, the same proportion to the total number of such offices as the population of the Scheduled Castes and the Scheduled Tribes respectively in the State bears to the total population of the State ; and