CREATE TABLE table_77868 ("System" TEXT, "Band" FLOAT, "Uplink  ( MHz ) " TEXT, "Downlink  ( MHz ) " TEXT, "Channel number" TEXT)

What band is the highest and has a System of gsm-450?
SELECT MAX("Band") FROM table_77868 WHERE "System" = 'gsm-450'
SELECT MAX("Band") FROM "table_77868" WHERE "System" = 'gsm-450'