give the least number of times an episode was shown from 1997-1998
CREATE TABLE "season_6_1997_1998" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "director" text,
  "writer_s" text,
  "original_air_date" text,
  "production_code" text
);
SELECT MIN("no_in_season") FROM "season_6_1997_1998";