SQlite Full text search (FTS)?

I have question about FTS on sqlite. Create table : CREATE VIRTUAL TABLE mail USING fts3(subject, body);

Insert demo data

INSERT INTO mail(docid, subject, body) VALUES(1, 'software feedback' 'found it too slow');
INSERT INTO mail(docid, subject, body) VALUES(2, 'software feedback', 'no feedback');
INSERT INTO mail(docid, subject, body) VALUES(3, 'slow lunch order',  'was a software problem');

Code for search querry

SELECT * FROM mail WHERE subject MATCH 'software*';    ==> Selects rows 1 and 2
SELECT * FROM mail WHERE body    MATCH 'feedback';    ==>  Selects row 2
SELECT * FROM mail WHERE mail    MATCH 'software*';    ==> Selects rows 1, 2 and 3
SELECT * FROM mail WHERE mail    MATCH 'slow';        ==> Selects rows 1 and 3

However, when I want to search text in a word. ex: I want to search any word contain character "o": ex:

SELECT * FROM mail WHERE mail    MATCH 'o';

Can't not get any result! Can anyone help me?