I would say contact the listing agent but there doesnt appear to be any contact info for one. Have you done a "drive by" of the property? There could be a for lease sign in the front. if so, I would call that number and ask.
Not sure which property you're inquiring about. I clicked on the Trulia link but it's showing as one that Trulia can't find. I also looked up 629 Park Ave. Long Beach on the MLS and am not finding anything either. What is the address of the property you're inquiring about?