CREATE TABLE table_10873 ("Date" TEXT, "Round" TEXT, "Opponent" TEXT, "Venue" TEXT, "Result" TEXT, "Attendance" FLOAT)

Who was the opponent of the match in round sf with a result of 0-0?
SELECT "Opponent" FROM table_10873 WHERE "Round" = 'sf' AND "Result" = '0-0'
SELECT "Opponent" FROM "table_10873" WHERE "Result" = '0-0' AND "Round" = 'sf'