CREATE TABLE temperature (city_id NUMBER, jan NUMBER, feb NUMBER, mar NUMBER, apr NUMBER, jun NUMBER, jul NUMBER, aug NUMBER, sep NUMBER, oct NUMBER, nov NUMBER, dec NUMBER)
CREATE TABLE hosting_city (year NUMBER, match_id NUMBER, host_city CLOB)
CREATE TABLE city (city_id NUMBER, city CLOB, hanzi CLOB, hanyu_pinyin CLOB, regional_population NUMBER, gdp NUMBER)
CREATE TABLE match (match_id NUMBER, date CLOB, venue CLOB, score CLOB, result CLOB, competition CLOB)

Find the GDP of the city with the largest regional population.
SELECT gdp FROM city ORDER BY regional_population DESC LIMIT 1
SELECT "gdp" FROM "city" ORDER BY "regional_population" DESC FETCH FIRST 1 ROWS ONLY