Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_77443 ( "Tie no" real, "Home team" text, "Score" text, "Away team" text, "Date" text )

### Question ###
What is the average Tie no when the date is Birmingham City?

### Accurate SQL ###

SELECT AVG("Tie no") FROM table_77443 WHERE "Date" = 'birmingham city'