A federal judge approved an emergency restraining order against and froze the assets of a father and son the U.S. Securities and Exchange Commission accuses of operating a $135 million Ponzi scheme involving South Side real estate.Judge John Z. Lee granted the temporary restraining order on Friday in the case the SEC brought against Equitybuild Inc., Equitybuild Finance LLC and company owners Jerome Cohen and his son Shaun Cohen.The SEC alleges the Cohens raised at least $135 million by selling securities to more than 900 …