Who was the winner when the General classification was held by Miguel Indurain, the Points classification held by Mario Cipollini, the Mountains classification held by Claudio Chiappucci, and the Young RIder classification held by Pavel Tonkov?
CREATE TABLE "classification_leadership_by_stage" (
  "stage" text,
  "winner" text,
  "general_classification" text,
  "points_classification" text,
  "mountains_classification" text,
  "young_rider_classification" text,
  "intergiro_classification" text,
  "trofeo_fast_team" text
);
SELECT "winner" FROM "classification_leadership_by_stage" WHERE "general_classification"='miguel indurain' AND "points_classification"='mario cipollini' AND "mountains_classification"='claudio chiappucci' AND "young_rider_classification"='pavel tonkov';