human
Considering the provided database schema and associated query, produce SQL code to retrieve the answer to the query. 
###Database Schema: City / Municipality, No. of s Barangay, District, Area (km²), Population (2010), Income class (2007), ZIP code, Mayor
###Question: What are all the metropolis / municipality where mayor is helen c. De castro
gpt
SELECT City / Municipality FROM table WHERE Mayor = Helen C. De Castro