SQL> create table t (col integer primary key)
  2  ORGANIZATION INDEX 
  3  /

Table created.

SQL> select * from user_tables where table_name='T';
TABLE_NAME                     Tablespace        CLUSTER_NAME                   IOT_NAME                       STATUS
------------------------------ ----------------- ------------------------------ ------------------------------ --------
  PCT_FREE   PCT_USED  INI_TRANS  MAX_TRANS INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS MAX_EXTENTS PCT_INCREASE  FREELISTS
---------- ---------- ---------- ---------- -------------- ----------- ----------- ----------- ------------ ----------
FREELIST_GROUPS LOG B   NUM_ROWS     BLOCKS EMPTY_BLOCKS  AVG_SPACE  CHAIN_CNT AVG_ROW_LEN AVG_SPACE_FREELIST_BLOCKS
--------------- --- - ---------- ---------- ------------ ---------- ---------- ----------- -------------------------
NUM_FREELIST_BLOCKS DEGREE     INSTANCES  CACHE TABLE_LO SAMPLE_SIZE LAST_ANALYZED       PAR IOT_TYPE     T S NES
------------------- ---------- ---------- ----- -------- ----------- ------------------- --- ------------ - - ---
BUFFER_ ROW_MOVE GLO USE DURATION        SKIP_COR MON CLUSTER_OWNER                  DEPENDEN COMPRESS DRO
------- -------- --- --- --------------- -------- --- ------------------------------ -------- -------- ---
T                                                                                                              VALID
         0          0          0          0
                    N
                             1          1     N ENABLED                                  NO  IOT          N N NO
        DISABLED NO  NO                  DISABLED YES                                DISABLED DISABLED NO

1 row selected.

SQL> select object_id from dba_objects where object_name='T';
 OBJECT_ID
----------
     54683

SQL> select * from user_extents where segment_name like '%54683';
SEGMENT_NAME                   PARTITION_NAME                 SEGMENT_TYPE       TABLESPACE_NAME
------------------------------ ------------------------------ ------------------ ------------------------------
 EXTENT_ID      BYTES     BLOCKS
---------- ---------- ----------
SYS_IOT_TOP_54683                                             INDEX              TS_D01
         0      65536          8

SQL> create table t (col integer primary key)
  2  ORGANIZATION INDEX 
  3  /


SQL> select TABLE_NAME,TABLESPACE_NAME from user_tables where table_name='T';

TABLE_NAME                     TABLESPACE_NAME
------------------------------ ------------------------------
T

Elapsed: 00:00:00.59

BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
PL/SQL Release 10.2.0.4.0 - Production
CORE    10.2.0.4.0      Production
TNS for IBM/AIX RISC System/6000: Version 10.2.0.4.0 - Productio
NLSRTL Version 10.2.0.4.0 - Production

Elapsed: 00:00:00.57