All persons who are in whole or in part of Indian blood or descent who are entitled to an allotment of land under any law of Congress, or who claim to be so entitled to land under any allotment Act or under any grant made by Congress, or who claim to have been unlawfully denied or excluded from any allotment or any parcel of land to which they claim to be lawfully entitled by virtue of any Act of Congress, may commence and prosecute or defend any action, suit, or proceeding in relation to their right thereto in the proper district court of the United States; and said district courts are given jurisdiction to try and determine any action, suit, or proceeding arising within their respective jurisdictions involving the right of any person, in whole or in part of Indian blood or descent, to any allotment of land under any law or treaty (and in said suit the parties thereto shall be the claimant as plaintiff and the United States as party defendant); and the judgment or decree of any such court in favor of any claimant to an allotment of land shall have the same effect, when properly certified to the Secretary of the Interior, as if such allotment had been allowed and approved by him, but this provision shall not apply to any lands now held by either of the Five Civilized Tribes, nor to any of the lands within the Quapaw Indian Agency: Provided, That the right of appeal shall be allowed to either party as in other cases.