CREATE TABLE table_55039 ("Home team" TEXT, "Home team score" TEXT, "Away team" TEXT, "Away team score" TEXT, "Venue" TEXT, "Crowd" FLOAT, "Date" TEXT)

If the Away team is essendon, what was the Date they played?
SELECT "Date" FROM table_55039 WHERE "Away team" = 'essendon'
SELECT "Date" FROM "table_55039" WHERE "Away team" = 'essendon'