CREATE TABLE table_38881 ("Rider" TEXT, "Bike" TEXT, "Laps" FLOAT, "Time" TEXT, "Grid" FLOAT)

What is the Grid for Rider Ruben Xaus?
SELECT MIN("Grid") FROM table_38881 WHERE "Rider" = 'ruben xaus'
SELECT MIN("Grid") FROM "table_38881" WHERE "Rider" = 'ruben xaus'