Spanish to English Law/Patents Government / Politics

This is from a Boletín Oficial de Estado from Spain 1959, discussing decrees that promote people to different positions in the court system. There are several short entries, many of which talk about people being promoted and include a short phrase set out by commas, of "en turno segundo" or "en turno tercero" or "en turno cuatro" and I just can't figure out what it means. Your suggestions are greatly appreciated. Some examples:

Decreto 123/1959, de 4 de junio, pro el que se promueve, en turno segundo, a la plaza de Magistrado de ascenso a don Fulano de Tal, Magistrado de entrada

Decreto 456/1959, de 11 de junio, por el que se promueve, en turno tercero, a la plaza de Magistrado de término a don Fulanito de Tal, Magistrado de ascenso.

Thanks for your recommendations!