CREATE TABLE table_1309 ("Series #" FLOAT, "Season #" FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "U.S. viewers  ( millions ) " CLOB)

Who was the writer when there were 15.85 million US viewers?
SELECT "Written by" FROM table_1309 WHERE "U.S. viewers (millions)" = '15.85'
SELECT "Written by" FROM "table_1309" WHERE "U.S. viewers (millions)" = '15.85'