CREATE TABLE table_66643 ("Tie no" CLOB, "Home team" CLOB, "Score" CLOB, "Away team" CLOB, "Attendance" CLOB)

What is the tie no that has southport as the away team?
SELECT "Tie no" FROM table_66643 WHERE "Away team" = 'southport'
SELECT "Tie no" FROM "table_66643" WHERE "Away team" = 'southport'