No elected Clarke County official may assume a supernumerary office after the effective date of this amendment. Any person who, on the effective date of this amendment, is entitled to participate in a supernumerary program may continue to participate in that supernumerary program, which shall include the assumption of a supernumerary office according to the terms and conditions of the law which established the particular supernumerary program. Any elected Clarke County official may participate in the Employees' Retirement System of Alabama upon the same terms and conditions as may be specified by law for any other employee in the same retirement system. An elected Clarke County official holding office at the effective date of this amendment shall be eligible to purchase service credit in the Employees' Retirement System for the time the elected county official has served in the current office; provided, however, the elected county official shall forego the assumption of a supernumerary office. For purposes of this amendment, the term "elected Clarke County official" shall mean any person elected to a full-time Clarke County office, and shall include any person appointed to serve the remaining term of an elected county official, but shall not include a judge, district attorney, legislator, constable, board of education member, any official elected from a judicial circuit, or any official who is allowed by law to participate in any other retirement system.