Question: What is the name of the league that celebrated its 87th season, in which Club Deportivo Leganés participated in?
Sentence (from "2016–17 Ergotelis F.C. season"): The season marked the beginning of a new era in the club's history, as the previous Football Club opened winding-up proceedings entering into liquidation, a process that allowed the parent sport club G.S. Ergotelis to form a new football department eligible to compete in the Gamma Ethniki under new leadership, free of the financial obligations of the previous administration.
Relevant evidence: No