from collections import defaultdict
list_tpl = [(4, 9), (4, 0), (5, 6), (5, 83), (4, 3), (6, 11)]
_map = defaultdict(list)
for key, val in list_tpl:
_map[key].append(val)
result = [(key, *val) for key, val in _map.items()]
print(result)
'''
run:
[(4, 9, 0, 3), (5, 6, 83), (6, 11)]
'''