Which episode in the series drew 3.6 million U.S. viewers? 
CREATE TABLE "table1_11111116_6" (
  "no_in_season" real,
  "no_in_series" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "u_s_viewers_million" text
);
SELECT MIN("no_in_series") FROM "table1_11111116_6" WHERE "u_s_viewers_million"='3.6';