CREATE TABLE "table1_21312959_1" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code" real,
  "us_viewers_millions" text
);

Question: What is the production code for the episode title "A Wrong Day's Journey into Right"?
SQL: SELECT "production_code" FROM "table1_21312959_1" WHERE "title"='\"A Wrong Day''s Journey into Right\"';

Question: How many episodes had the us viewers (millions) figure of 5.0?
SQL: SELECT COUNT("no_in_season") FROM "table1_21312959_1" WHERE "us_viewers_millions"='5.0';

Question: Who are the writers for the episode number in series 129?
SQL: SELECT "written_by" FROM "table1_21312959_1" WHERE "no_in_series"=129;

Question: What is the us viewers (millions) figure for the episode titled "Witch Wars"?
SQL: SELECT "us_viewers_millions" FROM "table1_21312959_1" WHERE "title"='\"Witch Wars\"';