CREATE TABLE table_28042 ("Series no." FLOAT, "No. in season" FLOAT, "Title" TEXT, "Written by" TEXT, "Directed by" TEXT, "Original air date" TEXT, "U.S. viewers  ( millions ) " TEXT)

What was the original air date where there were u.s. viewers (millions) is 5.60?
SELECT "Original air date" FROM table_28042 WHERE "U.S. viewers (millions)" = '5.60'
SELECT "Original air date" FROM "table_28042" WHERE "U.S. viewers (millions)" = '5.60'