lst_tpl = [(43, 'python'),
(16, 'java'),
(19, 'c'),
(43, 'c++'),
(27, 'c#'),
(43, 'php')]
seen = set()
result = [(x, y) for x, y in lst_tpl if not (x in seen or seen.add(x))]
print(result)
'''
run:
[(43, 'python'), (16, 'java'), (19, 'c'), (27, 'c#')]
'''