CREATE TABLE table_55559 ("Date" CLOB, "Opponent" CLOB, "Venue" CLOB, "Result" CLOB, "Attendance" FLOAT)

Which Date has an Opponent of manchester united, and a Venue A?
SELECT "Date" FROM table_55559 WHERE "Opponent" = 'manchester united' AND "Venue" = 'a'
SELECT "Date" FROM "table_55559" WHERE "Opponent" = 'manchester united' AND "Venue" = 'a'