CREATE TABLE table_30400 ("#  ( season # ) " TEXT, "No.  ( episode # ) " TEXT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Prod. code" TEXT)

What was the orginal air date for episodes with production code 2acx12?
SELECT "Original air date" FROM table_30400 WHERE "Prod. code" = '2ACX12'
SELECT "Original air date" FROM "table_30400" WHERE "Prod. code" = '2ACX12'