CREATE TABLE table_46693 ("Rider" TEXT, "Manufacturer" TEXT, "Laps" FLOAT, "Time/Retired" TEXT, "Grid" FLOAT)

What is the highest grid that tetsuya harada rode in?
SELECT MAX("Grid") FROM table_46693 WHERE "Rider" = 'tetsuya harada'
SELECT MAX("Grid") FROM "table_46693" WHERE "Rider" = 'tetsuya harada'