To be eligible to serve as a justice of the Supreme Court or a judge of the Court of Appeals, Circuit Court or District Court a person must be a citizen of the United States, licensed to practice law in the courts of this Commonwealth, and have been a resident of this Commonwealth and of the district from which he is elected for two years next preceding his taking office. In addition, to be eligible to serve as a justice of the Supreme Court or judge of the Court of Appeals or Circuit Court a person must have been a licensed attorney for at least eight years. No district judge shall serve who has not been a licensed attorney for at least two years.