party leader from to
party
leader
from
to
number parsed year month
number parsed year month
text text date date
scottish national party gordon wallace may 1974 may 1978
what is the total number of years gordon wallace and robert cunning spent in office .
WP VBD-AUX DT JJ NN IN NNS NNP NNP CC NNP JJ VBN IN NN .
6
select sum ( c4_number - c3_number ) from w where c2 in ( 'gordon wallace' , 'robert cunning' )