CREATE TABLE table_503 ("Season" CLOB, "Competition" CLOB, "Round" CLOB, "Club" CLOB, "1st leg" CLOB, "2nd leg" CLOB, "Aggregate" CLOB)

What is the round when 1st leg is 0 1?
SELECT "Round" FROM table_503 WHERE "1st leg" = '0–1'
SELECT "Round" FROM "table_503" WHERE "1st leg" = '0–1'