CREATE TABLE table_57518 ("Tie no" TEXT, "Home team" TEXT, "Score" TEXT, "Away team" TEXT, "Attendance" TEXT)

What is the tie number when the away team is Lewes?
SELECT "Tie no" FROM table_57518 WHERE "Away team" = 'lewes'
SELECT "Tie no" FROM "table_57518" WHERE "Away team" = 'lewes'