An intern shall not acquire tenure while serving on an internship credential. A person who, after completing a teaching internship program authorized pursuant to this article, is employed for at least one complete school year in a position requiring certification qualifications by the school district that employed the person as an intern during the immediately preceding school year and is reelected for the next succeeding school year to a position requiring certification qualifications shall, at the commencement of the succeeding school year, acquire tenure.