CREATE TABLE "jersey_progress" (
  "stage_winner" text,
  "general_classification" text,
  "young_classification" text,
  "sprint_classification" text,
  "aggressive_rider" text,
  "team_classification" text
);

Question: Which young classification has an aggressive rider of Tim Johnson?
SQL: SELECT "young_classification" FROM "jersey_progress" WHERE "aggressive_rider"='tim johnson';