Two sale deeds registered with different date which one is valid?

Ek vyakti ne1996 me ek plot k documents banaye,lekin wo document ko sub registrar k office me sirf execution karaya, lekin document registered isliye nahi hua kyoki suffiicient Stamp Duty paid nahi kiya gaya. Registrar ne kai notice bhege taki rest Stamp Duty pay karne ke liye. Lekin us vyakti ne pay karne k liye notice par likhkar saaf mana kar diya.2004 me hamare uncle ne wo hi plot ko 30yr ki Search karai & malum hua plot original owner k naam se registered hai uske baad original owner se 1-1-2004 ko plot (registered sale deed) kharida. Lekin jis vyakti ne 1996 ko plot sambandit document execution karaya the jab use malum hua ki hamare uncle ne 1-1-2004 ko plot kharid liya hai, toh usne 2-11-2004 ko plot k papers registered karaya. Hamare uncle ko original owner ne affidavit me likh k diya hai ki original owner ne 1996 me &1-1-2004 k pehle kisi bhi person ko wo plot nahi sale kiya.2-11-2004 ka registered doc. Ko null n void karne k liye 2005 m hamare uncle ne civic case lagayahai.