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 member ( member_id number, card_number text, name text, hometown text, level number )
TABLE: CREATE TABLE branch ( branch_id number, name text, open_year text, address_road text, city text, membership_amount text )
TABLE: CREATE TABLE membership_register_branch ( member_id number, branch_id text, register_year text )
TABLE: CREATE TABLE purchase ( member_id number, branch_id text, year text, total_pounds number )

### Question ###
What are the minimum and maximum membership amounts for all branches that either opened in 2011 or are located in London?

### Accurate SQL ###

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