What was Bob Jameson's lowest bonus where he had less than 15 rides?
CREATE TABLE "1965_season_finished_5th_39pts_out_of_18" (
  "rider" text,
  "matches" real,
  "rides" real,
  "bonus_pts" real,
  "total_points" real
);
SELECT MIN("bonus_pts") FROM "1965_season_finished_5th_39pts_out_of_18" WHERE "rider"='bob jameson' AND "rides"<15;