MUST DIE IN CHAIRJACKSON, Miss., April Mississippi supreme court today ruled that Grady White, Neshoba county night club owner, must die in the portable electric chair on May 15 for the murder of Sam McCune, employe of a vending machine company. Affirming the conviction of White, who will be the first white man to die in Mississippi’s electric chair, the high court failed to find reversible error in the refusal of a Neshoba county circuit court to giant change of venue requested by White's attorneys.