How many more people did the metropolitan statistical area have in 2013 than the Charleston-North Charleston Urban Area?
return the  metropolitan statistical area ;return the  Charleston-North Charleston Urban Area ;return people of #1 ;return people of #2 ;return #3 in  2013 ;return #4 in  2013 ;return number of  #5 ;return number of  #6 ;return the  difference of #7 and  #8
['select', 'select', 'project', 'project', 'filter', 'filter', 'aggregate', 'aggregate', 'arithmetic']