CREATE TABLE table_1757 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "U.S. viewers  ( millions ) " TEXT)

How many original air dates have U.S. Views (millions) of 19.49?
SELECT COUNT("Original air date") FROM table_1757 WHERE "U.S. viewers (millions)" = '19.49'
SELECT COUNT("Original air date") FROM "table_1757" WHERE "U.S. viewers (millions)" = '19.49'