What is the year when they did not qualify for the playoff and the Regular Season shows as 10th?
CREATE TABLE "year_by_year" (
  "year" real,
  "division" real,
  "league" text,
  "regular_season" text,
  "playoffs" text,
  "open_cup" text
);
SELECT COUNT("year") FROM "year_by_year" WHERE "playoffs"='did not qualify' AND "regular_season"='10th';