Name the least tries for when w is 4
{'header': ['Team', 'P', 'W', 'D', 'L', 'Tries for', 'Tries against', 'Try diff', 'Points for', 'Points against', 'Points diff', 'Pts'], 'page_title': '1996–97 European Challenge Cup', 'page_id': '', 'types': ['text', 'real', 'real', 'real', 'real', 'real', 'real', 'text', 'real', 'real', 'text', 'real'], 'id': '1-16770037-4', 'section_title': 'Pool 3', 'caption': 'Pool 3', 'rows': [['Northampton Saints', '5', '5', '0', '0', '28', '12', '+16', '207', '88', '+119', '10'], ['Toulon', '5', '4', '0', '1', '22', '10', '+12', '164', '102', '+62', '8'], ['Orrell', '5', '2', '0', '3', '18', '22', '−4', '122', '173', '−51', '4'], ['Connacht', '5', '2', '0', '3', '9', '17', '−8', '94', '131', '−37', '4'], ['Dunvant', '5', '1', '0', '4', '15', '22', '−7', '106', '169', '−63', '2'], ['Petrarca', '5', '1', '0', '4', '10', '19', '−9', '118', '148', '−30', '2']], 'name': 'table_16770037_4'}