Among the facilities that have undergone at least one inspection in 2010, how many of them are in ward no.42?
in 2010 refers to inspection_date like '2010%'; in ward no.42 refers to ward = 42
SELECT COUNT(DISTINCT T1.license_no) FROM inspection AS T1 INNER JOIN establishment AS T2 ON T1.license_no = T2.license_no WHERE strftime('%Y', T1.inspection_date) = '2010' AND T2.ward = 42