CREATE TABLE table_43667 ("Match" TEXT, "Date" TEXT, "Location" TEXT, "Lineup" TEXT, "Result" TEXT, "Competition" TEXT)

On What Date is the Competition Semifinal that has a result of 2-1 aet?
SELECT "Date" FROM table_43667 WHERE "Competition" = 'semifinal' AND "Result" = '2-1 aet'
SELECT "Date" FROM "table_43667" WHERE "Competition" = 'semifinal' AND "Result" = '2-1 aet'