CREATE TABLE table_31978 ("Candidate" TEXT, "Party" TEXT, "Constituency" TEXT, "Year" TEXT, "Days" TEXT)

What year was Hazel Grove the constituent for the liberal party?
SELECT "Year" FROM table_31978 WHERE "Party" = 'liberal' AND "Constituency" = 'hazel grove'
SELECT "Year" FROM "table_31978" WHERE "Constituency" = 'hazel grove' AND "Party" = 'liberal'