Tax on sale of leasehold plot alongwith factory building

My client selling MIDC leasehold plot alongwith factory building my query is how to calculate capital gain ? On full amount short term capital gain as factory building is depriciable assets attracting 30% ??? Will it be treated as lumpsum sale and attract 20% or 10 % long term capital gain tax ??? Will be able to treat sale of plot leasehold rights by deed of assignments as long term capital gain ?? Tax will be at 20% ? Or 10 ?? If indexation not opted ? IN THIS CASE ANY DEDUCTION ALLOWABLE U/S 54 EC OR ANY OTHER IF AMOUNT INVESTED AND LIMIT IF ANY ?? & in this case factory building being depriciable assets gain will be short term in nature on it ?? Tax @ 30 % ?? Assessee is FIRM