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 branch ( membership_amount INTEGER, open_year VARCHAR, city VARCHAR )

### Question ###
Show minimum and maximum amount of memberships for all branches opened in 2011 or located at city London.

### Accurate SQL ###

SELECT MIN(membership_amount), MAX(membership_amount) FROM branch WHERE open_year = 2011 OR city = 'London'