(a) No person serving as commissioner shall be eligible during his term of service and for a period of 12 months after the expiration or termination of his term of service to be a candidate in any primary, special, or general election for any state or federal elective office or to hold any such office.

(b) Subsection (a) of this Code section shall not be construed to prevent any commissioner or former commissioner from being appointed to any elective office, to disqualify him from being a candidate in any election to succeed himself in any such office to which he has been appointed, or to disqualify him from holding any such office in the event he is elected to and otherwise qualifies for the office.