what is the minimum stage where mountains classification is aitor osa and aitor gonzález won?
CREATE TABLE "jersey_progress" (
  "stage" real,
  "winner" text,
  "general_classification" text,
  "points_classification" text,
  "mountains_classification" text,
  "combination_classification" text,
  "team_classification" text
);
SELECT MIN("stage") FROM "jersey_progress" WHERE "mountains_classification"='Aitor Osa' AND "winner"='Aitor González';