CREATE TABLE table_39871 ("Team #1" TEXT, "Agg." TEXT, "Team #2" TEXT, "1st leg" TEXT, "2nd leg" TEXT)

When Estudiantes was team #2, what was their agg. value?
SELECT "Agg." FROM table_39871 WHERE "Team #2" = 'estudiantes'
SELECT "Agg." FROM "table_39871" WHERE "Team #2" = 'estudiantes'