Question: What was the attendance when the Southend United was the home team?
SQL: SELECT "Attendance" FROM "2-17814838-3" WHERE "Home team" = 'Southend United';

Question: Who was the away team that played Northampton Town at home with a tie number of replay?
SQL: SELECT "Away team" FROM "2-17814838-3" WHERE "Tie no" = 'replay' AND "Home team" = 'Northampton Town';