CREATE TABLE table_28696 ("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  ( millions ) " TEXT)

What is the original air date of 'Helen Back Again'?
SELECT "Original air date" FROM table_28696 WHERE "Title" = 'Helen Back Again'
SELECT "Original air date" FROM "table_28696" WHERE "Title" = 'Helen Back Again'