If (you use mysql) {
put limit to the result of you sql query
ex:
$query = "SELECT id,title_text,body_text,title_align,body_align,title_font,title_font_size,body_font,body_font_size,title_color,body_color,picture_data,picture_filesize,picture_filetype,picture_filename,picture_align from content WHERE username='$username' order by id desc limit 1";
} else {
find out with MSSQL, PSQL or whatever
}