Who is the head of the state where the most crowded city belongs?
head of the state refers to HeadOfState; most crowded city refers to MAX(Population);
SELECT T1.HeadOfState FROM Country AS T1 INNER JOIN City AS T2 ON T1.Code = T2.CountryCode ORDER BY T2.Population DESC LIMIT 1
database name:db_id world
City table City Cols: ID dtype integer, Name dtype text, Country Code dtype text, District dtype text, Population dtype integer, 
Country table Country Cols: Code dtype text, Name dtype text, Continent dtype text, Region dtype text, Surface Area dtype real, Independence Year dtype integer, Population dtype integer, Life Expectancy dtype real, Gross National Product dtype real, Gross National Product Old dtype real, Local Name dtype text, Government Form dtype text, Head Of State dtype text, Capital dtype integer, Code2 dtype text, 
CountryLanguage table CountryLanguage Cols: Country Code dtype text, Language dtype text, Is Official dtype text, Percentage dtype real, 
