What is the episode number with a title "baby's a rock 'n' roller"?
CREATE TABLE "table1_27987623_1" (
  "series_episode" real,
  "season_episode" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "u_s_viewers_in_million" text
);
SELECT MIN("series_episode") FROM "table1_27987623_1" WHERE "title"='\"Baby''s a Rock ''N'' Roller\"';