which episode of the season aired on october20,2012
CREATE TABLE "table1_29196086_4" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text
);
SELECT MAX("no_in_season") FROM "table1_29196086_4" WHERE "original_air_date"='October20,2012';