A special election Tuesday in New York decided the fates of 11 open seats in the state legislature — including two key Democratic victories in the state Senate. Democrat Luis Sepulveda easily won his race in the 32nd District in the Bronx, where he was heavily favored. Democrat Shelley Mayer also defeated Republican Julie Killian in a closely watched contest in the 37th District in part of Westchester, New York’s northern suburbs. Mayer’s victory in the swing district is a reassuring sign for Democrats as they try to take full control of the state Senate in the fall.But the Republicans will retain control of the state Senate thanks to one renegade Democrat.