CREATE TABLE table_28371 ("Name" TEXT, "GP" FLOAT, "Solo" FLOAT, "Ast" FLOAT, "Total" FLOAT, "TFL-Yds" TEXT, "No-Yds" TEXT, "BrUp" FLOAT, "No.-Yds" TEXT, "Avg" TEXT, "TD" FLOAT, "Long" FLOAT, "Rcv-Yds" TEXT, "FF" FLOAT, "Blkd Kick" FLOAT)

What is the highest ff when solo is 56?
SELECT MAX("FF") FROM table_28371 WHERE "Solo" = '56'
SELECT MAX("FF") FROM "table_28371" WHERE "Solo" = '56'