Query: When was Espanyol's margin win of 6-0?
Context: In the primera división league table, Espanyol has only managed to end above Barça on three occasions from 80 seasons (1928–2015) and the only all-Catalan Copa del Rey final was won by Barça in 1957. Espanyol has the consolation of achieving the largest margin win with a 6–0 in 1951, while Barcelona's biggest win was 5–0 on five occasions (in 1933, 1947, 1964, 1975 and 1992). Espanyol achieved a 2–1 win against Barça during the 2008–09 season, becoming the first team to defeat Barcelona at Camp Nou in their treble-winning season.