What is the total of the team with a T score less than 6.8?
CREATE TABLE "group_3_balls_2_ropes" (
  "nation" text,
  "t_score" real,
  "a_score" real,
  "e_score" real,
  "total" real
);
SELECT SUM("total") FROM "group_3_balls_2_ropes" WHERE "t_score"<6.8;