In which city is there a greater number of schools that have received donations of less than 10 dollars?
received donations of less than 10 dollars refers to dollar_amount = 'under_10'; city refers to school_city


SELECT T2.school_city FROM donations AS T1 INNER JOIN projects AS T2 ON T1.projectid = T2.projectid WHERE T1.dollar_amount = 'under_10' GROUP BY T2.school_city ORDER BY COUNT(T2.schoolid) DESC LIMIT 1