S. 143(2): Assessment-Validity-Notice under section 143(2) issued by Income-tax Officer-Additional grounds-Legal issue-Jurisdictional Assessing Officer, having regard to quantum of returned income, being Deputy Commissioner-No order transferring case to Deputy Commissioner-Income-tax Officer lacking jurisdiction-Deputy Commissioner completing assessment without valid notice-Defect not curable-Assessment quashed. [S. 124(3), 127, 254, ITAT Rules, 1963, R. 11]