Tax return for dependent of H1B


I came to US in November 2013 on H1B and my family came in December in H4. This is our first trip to US. I want to know whether I can claim my wife and kid as dependent and get an exemption while filing tax return for 2013? Is there any minimum time period which dependent needs to be in US to get a tax exemption? 


Consult a tax guy. It is best to get proper advice for the 1st time and then do it yourself from next year