The Mayor shall appoint three persons, who shall be electors of the City of Eastlake and who shall constitute the Civil Service Commission of the City of Eastlake, provided, however, that members, of the existing Civil Service Commission of the City of Eastlake, shall continue in office for the terms for which they have been appointed and until their successors are appointed and qualified. The term of office of the members of the Commission shall not exceed six years and any vacancy occurring other than expiration of term shall be filled for the unexpired portion of the term only and in the manner designated above for the original appointments.