Hi! This should work:
import datasets
features = datasets.Features({"text": datasets.Value("string"), "label": datasets.ClassLabel(names=['not_equivalent', 'equivalent'])})
dset = datasets.load_dataset("csv", data_files="train.txt", sep=";", names=["text", "label"], features=features)

Also note that the label column in your csv file has to contain numbers as labels (0 and 1) and not strings (not_equivalent and equivalent), otherwise you’ll get an error.