CREATE TABLE table_51090 ("Tie no" TEXT, "Home team" TEXT, "Score" TEXT, "Away team" TEXT, "Date" TEXT)

What is Date, when Tie No is 'Replay', and when Away Team is 'Crystal Palace'?
SELECT "Date" FROM table_51090 WHERE "Tie no" = 'replay' AND "Away team" = 'crystal palace'
SELECT "Date" FROM "table_51090" WHERE "Away team" = 'crystal palace' AND "Tie no" = 'replay'