CREATE TABLE table_16783 ("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)

Who wrote an episode watched by 19.01 million US viewers?
SELECT "Written by" FROM table_16783 WHERE "U.S. viewers (millions)" = '19.01'
SELECT "Written by" FROM "table_16783" WHERE "U.S. viewers (millions)" = '19.01'