CREATE TABLE table_203_688 (id DECIMAL, "category" TEXT, "speed\ ( km/h ) " DECIMAL, "speed\ ( mph ) " DECIMAL, "vehicle" TEXT, "pilot" TEXT, "date" TEXT)

what was the top speed in miles per hour ?
SELECT MAX("speed\n(mph)") FROM table_203_688
SELECT MAX("speed\n(mph)") FROM "table_203_688"