No person shall be eligible for any city office unless he has been a resident of the city for at least one year immediately preceding his election, nor shall any person be eligible for the office of Councilman to represent any ward unless for the last six months of his residence in the city he has been a resident of such ward. Should any city officer cease to be a resident of the city, or any Councilman representing any ward cease to be a resident of such ward, during his term of office, such office shall at once become vacant.
(IC 36-4-5-2, 36-4-6-2, 36-4-10-3)