Why Run? Why, anyway, does a woman want to enter the political arena and take on those long State House sessions? As Mrs. Marcian E. Acres, House Republican candidate from Malden, explains, she and other woman have discussed affairs of government and tax structure in study groups. "Why not put some of it to use?" Mrs. Acres feels the Legislature must face a decision Mrs. Acres on a sales tax on luxury items to finance state aid for education. The mother of a 3 1/2-year-old youngster, Mrs. Acres holds a college degree in social service and is an executive in the Red Cross and Malden TB Association. After the children are grown, many women want to give time