CREATE TABLE table_52599 ("Stage" CLOB, "Winner" CLOB, "General classification" CLOB, "Points classification" CLOB, "Trofeo Fast Team" CLOB)

Which stage has a Winner of lucien van impe?
SELECT "Stage" FROM table_52599 WHERE "Winner" = 'lucien van impe'
SELECT "Stage" FROM "table_52599" WHERE "Winner" = 'lucien van impe'