What is the Copa Libertadores 1999 result for team vasco, which made the group stage in the Copa Mercosur 1999?
CREATE TABLE "brazilian_clubs_in_international_competi" (
  "team" text,
  "copa_libertadores_1999" text,
  "copa_mercosur_1999" text,
  "copa_conmebol_1999" text,
  "intercontinental_cup_1999" text
);
SELECT "copa_libertadores_1999" FROM "brazilian_clubs_in_international_competi" WHERE "copa_mercosur_1999"='group stage' AND "team"='vasco';