CREATE TABLE table_51012 ("Tie no" TEXT, "Home team" TEXT, "Score" TEXT, "Away team" TEXT, "Attendance" TEXT)

What was the Tie no when the away team was east thurrock united?
SELECT "Tie no" FROM table_51012 WHERE "Away team" = 'east thurrock united'
SELECT "Tie no" FROM "table_51012" WHERE "Away team" = 'east thurrock united'