CREATE TABLE table_name_8 (saffir_simpson_category INT, nhc_advisory_number VARCHAR)

What was the highest SaffirSimpson with an NHC advisory of 18?
SELECT MAX(saffir_simpson_category) FROM table_name_8 WHERE nhc_advisory_number = "18"
SELECT MAX("saffir_simpson_category") FROM "table_name_8" WHERE "18" = "nhc_advisory_number"