CREATE TABLE table_24860 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" TEXT, "U.S. viewers  ( million ) " TEXT)

What is the air date of the episode with the production code 6acx19?
SELECT "Original air date" FROM table_24860 WHERE "Production code" = '6ACX19'
SELECT "Original air date" FROM "table_24860" WHERE "Production code" = '6ACX19'