CREATE TABLE table_71067 ("Stage" TEXT, "Date" TEXT, "Course" TEXT, "Distance" TEXT, "Winner" TEXT, "Race Leader" TEXT)

Which date has a Race Leader of hermann buse ( ger ), and a Stage of 5?
SELECT "Date" FROM table_71067 WHERE "Race Leader" = 'hermann buse ( ger )' AND "Stage" = '5'
SELECT "Date" FROM "table_71067" WHERE "Race Leader" = 'hermann buse ( ger )' AND "Stage" = '5'