§ 15. Vacancies. If a vacancy shall occur, otherwise than by
expiration of term, in an elective office of the city, including that of
supervisor, the mayor shall appoint a person to fill such vacancy. The
person so appointed to such vacancy shall hold office until the
commencement of the political year next succeeding the first annual
election after the happening of the vacancy at which a successor can be
elected for the balance of the unexpired term, if any. If a vacancy
shall occur in an appointive office of the city, otherwise than by
expiration of term, the officer, officers, board or body authorized to
make appointment to such office for the full term shall appoint a person
to fill such vacancy for the balance of the unexpired term.