CREATE TABLE "classification_leadership_by_stage" (
  "stage" text,
  "winner" text,
  "general_classification" text,
  "points_classification" text,
  "trofeo_fast_team" text
);

Question: What was the stage of team Once?
SQL: SELECT "stage" FROM "classification_leadership_by_stage" WHERE "trofeo_fast_team"='once';

Question: Which team had a final stage when Claudio Chiappucci had the points?
SQL: SELECT "trofeo_fast_team" FROM "classification_leadership_by_stage" WHERE "points_classification"='claudio chiappucci' AND "stage"='final';

Question: What stage did team Carrera Jeans-Tassoni have when Mario Cipollini won and Claudio Chiappucci had the points?
SQL: SELECT "stage" FROM "classification_leadership_by_stage" WHERE "trofeo_fast_team"='carrera jeans-tassoni' AND "winner"='mario cipollini' AND "points_classification"='claudio chiappucci';