instruction: when was the first time that patient 030-56105 had the mchc minimum value in 04/2104?
response: SELECT lab.labresulttime FROM lab WHERE lab.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '030-56105')) AND lab.labname = 'mchc' AND STRFTIME('%y-%m', lab.labresulttime) = '2104-04' ORDER BY lab.labresult, lab.labresulttime LIMIT 1