ON MONDAY NIGHT, JULY 13, THE EVE of baseball's All-Star game, cable offers a wonderful nostalgia double-header. Baltimore's new Oriole Park at Camden Yards was an attempt to re-create the cozy baseball stadiums built in the early part of this century, and Last of America's Classic Ball-parka (Discovery, 9 P.M. ET), narrated by Jeff Daniels, looks at the few remaining originals: Tiger Stadium in Detroit, Fenway Park in Boston and Wrigley Field in Chicago. When It Was a Game II (HBO, July 13, 10 P.M. ET) reprises last summer's special, using abundant, fascinating 8-mm and 16-mm color film of major leaguers from the '30s, '40s and '50s taken by fans and players.