In case both datasets are of the same size you might also zip them and iterate them using a for loop as such:
from torch.utils.data import DataLoader

ds1 = [0, 1, 2, 3]
ds2 = [10, 11, 12, 13]

dl1 = DataLoader(ds1)
dl2 = DataLoader(ds2)
dl1_iter = iter(dl1)
dl2_iter = iter(dl2)

for s1, s2 in zip(dl1_iter, dl2_iter):
    print(s1)
    print(s2)

This yields:
tensor([0])
tensor([10])
tensor([1])
tensor([11])
tensor([2])
tensor([12])
tensor([3])
tensor([13])