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
which party had only one leader and only a three year office term ?
WDT NN VBD-AUX RB CD NN CC RB DT CD NN NN NN .
Independent
select c1 from w group by c1 having count ( c2 ) = 1 and c4_year - c3_year = 3