CREATE TABLE dbo.TestCluster
(
    TestClusterID INT NOT NULL
);

CREATE CLUSTERED INDEX CX_TestCluster --note there is no "UNIQUE" keyword here
ON dbo.TestCluster(TestClusterID);

SELECT SchemaName = s.name
    , TableName = o.name
    , IndexName = i.name
    , IndexType = i.type_desc
    , IsUnique = i.is_unique
FROM sys.indexes i
    INNER JOIN sys.objects o ON i.object_id = o.object_id
    INNER JOIN sys.schemas s ON o.schema_id = s.schema_id
WHERE s.name = 'dbo'
    AND o.name = 'TestCluster'
    AND i.type_desc = 'CLUSTERED';

SELECT  OBJECT_NAME(object_id) AS TableName ,
    name AS IndexName ,
    type_desc AS IndexType ,
    CASE WHEN is_unique = '1' THEN 'UNIQUE'
         WHEN is_unique = '0' THEN 'NON UNIQUE'
    END AS Index_Desc
FROM    sys.indexes
WHERE   type_desc = 'CLUSTERED'
    AND OBJECT_NAME(object_id) = 'MyTable';