What are the load shapes of all the short ellipse cars?
short refers to len = 'short'; ellipse cars refers to shape = 'ellipse'
SELECT load_shape FROM cars WHERE shape = 'ellipse' AND len = 'short'
database name:db_id trains
cars table cars Cols: id dtype integer, train id dtype integer, position dtype integer, shape dtype text, length dtype text, sides dtype text, roof dtype text, wheels dtype integer, load_shape dtype text, load number dtype integer, 
trains table trains Cols: id dtype integer, direction dtype text, 
