Transfer functions for MLP

Hi. I am totally new in this area. I want to classify a dataset to 2 classes {0,1} with a simple Mlp. These are my codes: net = newff(train_input',train_output',6,{'?','?'}); net = train(net,train_input',train_output'); y = sim(net,test_input');

which functions should I put instead of ''? '' .How can I make my last result of y including just 2 values 0 or 1.

THANK YOU

Thank you.