What is the minimum number which is for title The Enemy Within part 1?
CREATE TABLE "table1_18305523_1" (
  "num" real,
  "cover_date" text,
  "story_title" text,
  "writer_s" text,
  "artist_s" text,
  "letterer_s" text,
  "colourist_s" text,
  "editor_s" text,
  "comments" text
);
SELECT MIN("num") FROM "table1_18305523_1";