What is the highest stage number for a year later than 1948, leader at the summit was group, and finish was Bagnères-De-Bigorre?
CREATE TABLE "appearances_in_tour_de_france_since_1947" (
  "year" real,
  "stage" real,
  "start" text,
  "finish" text,
  "leader_at_the_summit" text
);
SELECT MAX("stage") FROM "appearances_in_tour_de_france_since_1947" WHERE "year">1948 AND "leader_at_the_summit"='group' AND "finish"='bagnères-de-bigorre';