CREATE TABLE table_1843 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "Production code" CLOB, "U.S. viewers  ( million ) " CLOB)

Who directed the episode seen by 3.93 million people in the US?
SELECT "Directed by" FROM table_1843 WHERE "U.S. viewers (million)" = '3.93'
SELECT "Directed by" FROM "table_1843" WHERE "U.S. viewers (million)" = '3.93'