CREATE TABLE table_27789 ("Stage" FLOAT, "Winner" TEXT, "General Classification" TEXT, "Mountains Classification" TEXT, "Sprint Classification" TEXT, "Young Rider Classification" TEXT, "Team Classification" TEXT, "Aggressive Rider" TEXT)

Who was the aggressive rider when the sprint classification was andr greipel and mountains classification was timothy roe?
SELECT "Aggressive Rider" FROM table_27789 WHERE "Sprint Classification" = 'André Greipel' AND "Mountains Classification" = 'Timothy Roe'
SELECT "Aggressive Rider" FROM "table_27789" WHERE "Mountains Classification" = 'Timothy Roe' AND "Sprint Classification" = 'André Greipel'