What is the lowest number of episodes in a series with an airing date of 12 jan- 6 feb?
CREATE TABLE "first_line_series" (
  "airing_date" text,
  "english_title_chinese_title" text,
  "number_of_episodes" real,
  "genre" text,
  "official_website" text
);
SELECT MIN("number_of_episodes") FROM "first_line_series" WHERE "airing_date"='12 jan- 6 feb';