ยง 11. Elective  officers.  There  shall  be  elected  by the qualified
  electors of the city, a mayor, comptroller, treasurer, president of  the
  common  council  and  four  assessors.    There  shall be elected by the
  qualified  electors  of  each  ward  of  the  city  an  alderman  and  a
  supervisor.    There  shall also be elected by the qualified electors of
  the city and of the wards thereof such other officers as may be provided
  by law.