AIADMK was leading in one of the 22 Assembly constituencies in Tamil Nadu Thursday, the Election Commission said. The AIADMK was leading arch rival DMK by a slender margin in Sattur, according to the data made available by the Election Commission. By-polls to the 22 seats, whose outcome will decide the fate of the AIADMK government headed by Chief Minister K Palaniswami, were held in two phases, on April 18 and May 21.