CREATE TABLE table_name_11 (number_of_mobile_phones VARCHAR2, last_updated_date VARCHAR2)

How many mobile phones were there as of April 2013?
SELECT number_of_mobile_phones FROM table_name_11 WHERE last_updated_date = "april 2013"
SELECT "number_of_mobile_phones" FROM "table_name_11" WHERE "april 2013" = "last_updated_date"