CREATE TABLE table_75803 ("Name" TEXT, "Novelty" TEXT, "Status" TEXT, "Authors" TEXT, "Location" TEXT, "Notes" TEXT)

What are the Notes of the dinosaur, whose Status is nomen dubium, and whose Location is China?
SELECT "Notes" FROM table_75803 WHERE "Status" = 'nomen dubium' AND "Location" = 'china'
SELECT "Notes" FROM "table_75803" WHERE "Location" = 'china' AND "Status" = 'nomen dubium'