What was the production code for the episode directed by Michael Morris?
CREATE TABLE "table1_23793770_1" (
  "no_in_series" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code" real,
  "u_s_viewers_millions" text
);
SELECT MIN("production_code") FROM "table1_23793770_1" WHERE "directed_by"='Michael Morris';