A Los Angeles County Superior Court judge has ruled that the Los Angeles Unified School District can proceed with its plans to demolish most of the historic Ambassador Hotel and build a $318-million campus, attorneys said Monday. The Los Angeles Conservancy and a coalition of local organizations had filed suit after the school board voted in October to build a facility for 4,200 kindergarten through high school students on the 24-acre property where movie stars, politicians and royalty once mingled and where Sen. Robert F. Kennedy was assassinated in 1968. The suit contended that the district had failed to comply...