EXCLUSIVE JUST LISTED MARBLE HILL  DEVELOPMENT or RENOVATION OPPORTUNITY: Two-Family House Zoned R6 Near Metro-North & Subway    This legal 2-family, detached stucco-sided house, built circa 1925, stands on a 3,700-sq.-ft. (35-by-100-ft. irregular) lot zoned R6. So bring your architect and your vision if you want to renovate or expand the house or develop the property further.    Top Unit - 2-bedrooom, 1-bath apartment.    Bottom Unit - 4-bedrooom, 1.5-bath duplex apartment with access to unfinished basement.    The house has front and back gardens, an attached 2-car garage and a private driveway.    The neighborhood of Marble Hill is a tiny sliver of Manhattan, separated from the rest of the island when the Harlem River Ship Canal was dug in 1895. It became physically attached to the Bronx in 1913, when the Spuyten Duyvil Creek to its north was filled in.    Very conveniently located for trains (Metro-North and No. 1 subway), buses, schools, Marble Hill Playground and nearby shopping on Broadway and 225th Street.