How to appeal against assessment order u/s 143

I HAVE BEEN SCRUTANISED FOR THE ASSESSMENT YEAR 209-10 U/S 142(2), FOR WHICH I HAVE NOT RESPONDED TO THE NOTICES SENT MULTIPLE TIMES, THEREFORE I HAAVE BEEN ISSUED  AN ASSESSMENT ORDER U/S 143 HAVING DEMAND OF RS 600,000/- AS PER THE DATA AVAILABLE WITH THE DEPATMENT, HENCE I PLANNED   TO APPLEAL AGAINT TO THE COMMISSIONER, CAN I APPEAL AGAINT IT TO THE COMMISIONER WITH THE HELP OF LAWYER OR BY ANY SKILLED ACA.