CREATE TABLE "table1_27714573_1" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code_s" real,
  "u_s_viewers_millions" text
);

Question: who are the directors of the episode that had 20.5 millions of north american viewers? 
SQL: SELECT "directed_by" FROM "table1_27714573_1" WHERE "u_s_viewers_millions"='20.5';

Question: how many millions of north american viewers had the episode whose director was Michael Lembeck? 
SQL: SELECT "u_s_viewers_millions" FROM "table1_27714573_1" WHERE "directed_by"='Michael Lembeck';

Question: who are the writers of the episode whose production code(s) is 225560? 
SQL: SELECT "written_by" FROM "table1_27714573_1" WHERE "production_code_s"=225560;

Question: who are the writers of the episode called "The one on the last night"?
SQL: SELECT "written_by" FROM "table1_27714573_1" WHERE "title"='\"The One on the Last Night\"';