Which season used production code "am10"?
CREATE TABLE "table1_23279434_1" (
  "series_num" real,
  "season_num" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code" text
);
SELECT COUNT("season_num") FROM "table1_23279434_1" WHERE "production_code"='AM10';