what was the first value of an osmolality, urine lab test in patient 72107 until 02/2103?
select labevents.valuenum from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 72107 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'osmolality, urine' ) and strftime('%y-%m',labevents.charttime) <= '2103-02' order by labevents.charttime asc limit 1