if you want to search tuple for any number which is present in tuple then you can use
a= [(1,2),(1,4),(3,5),(5,7)]
i=1
result=[]
for j in a:
if i in j:
result.append(j)
print(result)
You can also use if i==j[0] or i==j[index]
if you want to search a number in particular index